The present invention relates to a fluorescent lamp for general purpose lighting, and particularly relates to a fluorescent lamp suitable for realization of a compact and plain pendant having a high lumen output which is suitable for a living room, a dining room, or the like.
Conventionally, a pendant to be used in a living room, a dining room, or the like, is configured so that a plurality of circular fluorescent lamps different in size from each other are provided in two or three stages so as to make the lumen output high in order to satisfy a user's requirement for a high lumen output. However, this configuration has a disadvantage in that the fixture is large in size, and there is little freedom in design of the fixture. For example, in the case of using three circular fluorescent lamps, the thickness of the stack of three lamps reaches about 10 cm, so that it has been impossible to make the fixture plain. Accordingly, more compact fluorescent lamps have been required.
As a compact fluorescent lamp, such a U-shaped fluorescent lamp as disclosed in Japanese Patent Unexamined Publication No. 60-225346 has been developed and put into practical use.
The conventional U-shaped fluorescent lamp has an elongated shape, and in the case of a pendant using one U-shaped fluorescent lamp, therefore, there has been a disadvantage that the uniformity in angular distribution of light flux is poor. Further, even if a plurality of lamps are used parallelly, the shape of the fixture becomes inevitably square, and therefore there has been a disadvantage that fine appearance is spoiled unless each side of the square of the fixture is made parallel to a wall surface of a room. In either case, such a U-shaped compact fluorescent lamp has not been suitable for a pendant.